In recent years, there has been remarkable improvement in accuracy in various components in the electronic industry, and accordingly, there has been increasing demand for capability of cleaning the manufacturing environment. Especially, since chemical contamination and adhered particles on the surface of components greatly effects the yield and reliability of operation of products, significance of the cleaning step in the manufacturing process is great, and various cleaning methods are therefore being developed.
For example, as a method of cleaning a surface of an object to be cleaned (surface to be cleaned) such as semiconductor electronic device wafer, silicon wafer, hard disk, or the like, scrub cleaning using a sponge roller, which includes an elastic, cylindrical roller fixed to the outer circumference of a rotary axis where the roller is made of, for example, a polyvinyl acetal porous material, and multiple protrusions formed integrally on the outer peripheral surface of the roller body, is well known. Scrub cleaning means to brush and clean by bringing the multiple protrusions of the outer circumference portion of the roller body into contact with a surface to be cleaned, and rotating a sponge roller via the rotary axis while supplying water or other cleaning liquid to the contact portions thereof.